Electric switch



March 6, 1934. J. J. CASBY ELECTRIC SWITCH Filed Feb. 25, 19:52

Inventor: John J. Casbg, 5 W m His Attorneg.

Patented Mar. 6, 1934 UETED STATES PATENT OFFICE ELECTREC SWITCH Appiication February 25, 1932, Serial No. 5955106 Claims.

My invention relates to improvements in electric switches and more particularly to switch mechanisms of the automatic or trip-free type whereby it is impossible for an operator to close 5 a switch and hold it closed under the conditions for which the switch is intended to be open. An object of my invention is to provide an improved automatic trip-free mechanism which is comparatively simple and economical and in which the resetting of the trip-free feature is accomplished during the opening of the switch so that the operator does not have to give any special thought or attention to this feature before closing the switch.

My invention will be better understood from the following description when considered in con-- nection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. i is a side elevation of a closed circuit breaker embodying my invention; Fig. 2 is a partial side elevation of the circuit breaker shown in Fig. 1 with the mechanism in the switch open position, and Fig. 3 is a schematic diagram for illustrating the mechanics of the switch mechanism.

The illustrated embodiment of my invention is a manually operated circuit breaker having a support or base 4 on which are suitably mounted a terminal 5, relatively movable cooperating contacts 6 and 7, a combination blow-out and tripping electromagnet 8 which has one end of its coil connected to the movable contact '7 by a flexible lead 9 and the other end connected to a ter" minal 10. The base 4 is preferably of suitable insulating material. For tripping purposes the electromagnet 8 is provided with an armature 11 which may be set to respond to any desired value of current in the circuit controlled by the circuit breaker, as is well known to the art.

For operating the movable contact '7 I provide a trip-free switch mechanism whose parts are mounted on the base 4. This mechanism includes pivotally mounted operating and contact members, such as levers 12 and 13, and means for holding these members against relative movement including a trip-free latch 14 pivotally mounted on one of the members, the lever 13, as shown, and arranged to engage the other member, the lever 12. As illustrated, the levers l2 and 13 are pivotally associated for movement about a common fixed pivotal axis or pivot 15. The movable contact 7 and the trip free latch 14 are mounted on a pivot 16 carried by the contact lever 13. The latch 14 is biased for counterclockwise rotation on its pivot 16 to latching posi- (Cl. HEP-89) tion by suitabl means such as a spring 1'7 to engage a lug such as a roller 18 mounted on the upper end of the operating lever.

For effecting rotation of the movable contact 7 on its pivot 16 so as to obtain a contact cleaning or rubbing operation and for opening the circuit breaker, there is provided suitable biasing means such as a spring 19 which tends to turn the contact counter-clockwise on its pivot 16 and after a limited amount of such movement during the circuit opening operation causes the arm of the contact on the opposite side of the pivot from the contact to abut a stop 20 on the contact lever 13 and thus to effect a clockwise rotation of this lever. For effecting a clockwise rotation of the operating lever 12 during the opening movement of the mechanism so as to reset the trip-free latch and return the operating lever to the open circuit position, shown in Fig. 2, suitable biasing means, such as a spring 21 is provided. The movement of the operating lever 12 between the circuit opening and circuit closed positions is limited by stops 22, 23, respectively.

For holding the contact 7 in switch closed position, as shown in Fig. l, I provide means such as a holding latch 24 for engaging one or" the members 12, 13, upon counter-clockwise rotation or movement of the operating lever 12 in the switch closing direction whereby to hold the contacts 6 and 7 closed while the trip-free latch 14 is in engagement with the operating lever 12. The holding latch 24 is mounted on a pivot 25 and is arranged to engage a lug such as a roller 26 mounted on the contact lever 13. The holding latch is biased to latching position by suitable means, such as a spring 27. For releasing the trip and holding latches, I provide suitable means including a tripping element 28 which, as shown, is mounted on the pivot 25 and supported in the path of movement of the armature 11 by an extension or arm 29 on the holding latch 24. The trip lever 28 is provided with an extension having a roller 30, which engages the trip-free latch on counter-clockwise rotation of the trip lever so that on movement of the armature 11 to the attracted position both or" the latches 14 and 24 are disengaged from their respective members 13 and 12 to cause the opening operation of the circuit breaker and prevent the reclosing thereof and holding the circuit breaker closed while the predetermined condition iorwhich the armature 11 is set to respond exists.

Assuming the circuit breaker closed, as shown in Fig. 1, and that sufficient current due to an overload or a fault on the circuit controlled by the circuit breaker flows to cause the movement of the armature 11 of the electromagnet 8 to the attracted position, the trip lever 28 will be turned counter-clockwise and thereby engage and release the latches 24 and 14. As soon as the l tch 14 is released, the connection between the operating lever 12 and the contact lever 13 is broken so that relative movement between these levers may occur. Upon the release of the holding latch 24, the contact lever 13 is free to turn clockwise about its pivot 15 under the bias of the spring 19. As soon as the spring 19 has moved the contact lever far enough to cause the arm of the contact 7 to engage the stop 29, both the contact lever and the contact move as a unit about the pivot 15, thereby causing the separation of the contacts 6 and '7. In consequence of the clockwise rotation of the contact lever 13, the biasing action of the spring 21 causes a clockwise rotation of the operating lever 12 from the switch closed position to the switch open position, shown in Fig. 2, whereupon the trip-free latch 14 reengages the roller 18 on the operating lever and the parts are positioned, as shown in Fig. 2, so as to be ready for the switch closing movement without any necessity for the operator to reset the trip-free mechanism.

Now assuming the parts as shown in Fig. 2, a counter-clockwise turning f the operating lever 12 causes this lever, the contact lever 13 and the contact 7 to move a unit until the contact 7 engages the contact 6 whereupon movement of the contact 7 relatively to the levers 12 and 13 occurs until the holding latch 24 engages its roller 26 on the lever 13. The circuit breaker is then closed and latched. If upon the engagement of the contacts 6 and '7, the armature 11 is again moved to its attracted position due to the abnormal circuit condition still existing, the trip lever 28 will immediately be energized to discharge the latch 14 before the holding latch 24 can engage the contact lever 13. it will, therefore, be impossible for the operator to hold the circuit breaker closed.

Assuming the circuit breaker closed, as shown in Fig. 1, it will be noted that it can be opened merely by moving the operating lever 12 in a clockwise direction about its pivot 15. In this movement the roller 18 will be disengaged from the latch 14 and subsequently the upper end or the operating lever 12 will engage and release the holding latch thus permitting the spring 19 to move the contact 7 and the contact lever 13, as previously described and thereby opening the circuit.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown, but seek to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A switch mechanism including pivotally as sociated operating and contact members, rela tively movable cooperating contacts one of which is mounted on said contact member, means for holding said members against relative movement including a latch pivotally mounted on one of the members arranged to engage the other member, means directly engaging one of said members in switch closed position on movement of the operating member in switch closing direction for holding the contacts closed while said latch is in engagement with said other member including a tripping element for moving said latch and said engaging means from their holding positions.

2. A switch mechanism including pivotally ass ciated operating and contact levers, relatively movable cooperating contacts, one of which is mounted on said contact lever, means for holding said levers against relative movement including a trip-"tree latch pivotally mounted on the contact lever and arranged to engage the operating lever, a holding latch directly engaging said contact lever in the switch closed position on movement of the operating lever in switch closing direction for holding the contacts closed while the trip-free latch is in engagement with the operating lever, and means including a trip lever for moving both of said latches from their holding positions.

3. A switch mechanism including relatively movable operating and contact members, relatively movable cooperating contacts one of which is mounted on contact member, means for preventing relative movement of said operating and contact members including a latch mounted on one of the members and arranged to engage the other, means directly engaging said one of the in switch closing position on movement of said other member in switch closing direction for holding the contacts closed while said latch is in engagement with said other member, and means including a tripping element for moving said latch and engaging means from their holding positions.

a. [i switch mechanism including an operating lever and a contact lever having a common pivotal relatively movable cooperating contacts one of which is pivotally mounted on said contact lever, means for biasing the contact lever for switch opening movement, a trip-free latch for holding said levers against relative movement pivotally mounted on the contact lever and arranged to engage the operating lever, a holding latch directly engaging the contact lever in the switch closing position on movement or" the operating lever in switch closing direction for maintaining the switch closed against the effect of d biasing means while the trip-free latch is in engagement with the operating lever, and means including a trip lever for moving both of said latches from their holding positions.

5. A switch mechanism including relatively movable operating and contact members, relatively movable cooperating contacts arranged to be controlled by the movement of said members, means for holding said members against relative movement when said operating member is moved in one direction to cl se the switch, and means engaging one oi said members in switch closed position for holding said contacts closed, said holding means an said engaging means being mounted in the path of movement of a part of said other member whereby on a limited movement of said other member in another direction holding means and said engaging means are released to efiect the opening of said contacts.

JOHN J. CASBY. 

